Boiler Circulating Pump Injection Water 1

[dR3w]

Hi,

I am building a computer simulation of a forced circulation boiler, and have a few questions. Can someone explain the purpose of circulating pump injection water? Is it for sealing the pump? It appears that some of the injection water bleeds/leaks into the circulating water ... is this true? Also I noticed that the plant controls the injection water pump discharge valve on a pressure difference of approximately 40 psid. Is this pressure difference the difference between injection water pump discharge pressure, and the boiler circulating water pump discharge pressure?

Thanks in advance,

Drew

 

[bezemerg]

dR3W

Dear Drew,

I have been involved in this pumps and seals for over 20 years. It was a small part of my job.

These pumps are used to circulate water in a boiler and to crate a better mixture of temperature. That is the way they explained to me.

The pump must be able to handle a high static pressure and high temperature. To keep the seal relatively cool they use a pumping ring and pump water through a cooler and back in the stuffing box. The water in the stuffing box reaches approximately 50 degree C.

The heqd of the pump will be rather low, sometimes less than 10 or 20 m. The speed of the pump is low, the axial pressure high due to the high static pressure in the pump.

There will always be a small leakage from the inner part of the pump to the outer part, but q few droplets per hour. In general the pump last for many years.


Regards,

Gerrit Bezemer

gerrit.bezemer@pandora.be